Electrostatic discharge (ESD) clamps are used to protect internal circuits from being damaged by ESI) events accidentally happened during fabrication, packaging and testing processes. The ESD clamps are applied to input/output (I/O), power (VDD/VSS) and switch pads of the internal circuits. The ESD clamps are turned off below a normal operating limit of the internal circuits and are broken down and triggered to be turned on at a voltage beyond the normal operating limit and below breakdown or catastrophic destruction of the internal circuits.